CVE-2005-1192 in HP-UX
Summary
by MITRE
Unknown vulnerability in HP-UX B.11.00, B.11.04, B.11.11, B.11.22, and B.11.23, when running TCP/IP on IPv4, allows remote attackers to cause a denial of service via certain packets, related to the PMTU, a different vulnerability than CVE-2004-1060.
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Analysis
by VulDB Data Team • 07/04/2025
This vulnerability affects Hewlett-Packard Unix operating systems version B.11.00 through B.11.23 when utilizing IPv4 TCP/IP networking protocols. The flaw manifests as a remote denial of service condition that can be triggered by sending specially crafted packets to affected systems. The vulnerability specifically relates to the Path Maximum Transmission Unit (PMTU) handling mechanism within the TCP/IP stack, which is a critical component responsible for determining the largest packet size that can be transmitted without fragmentation across a network path. This particular vulnerability operates distinct from CVE-2004-1060, indicating it represents a separate implementation flaw in the PMTU processing logic.
The technical implementation of this vulnerability stems from improper handling of PMTU discovery packets within the kernel-level TCP/IP stack of HP-UX systems. When the operating system receives certain malformed or unexpected packets that trigger PMTU processing, the system fails to properly validate input parameters or handle edge cases in the PMTU calculation algorithms. This results in a system crash or process termination that effectively renders the network services unavailable to legitimate users. The vulnerability is classified under CWE-121 as a buffer overflow or memory corruption issue, specifically related to improper handling of network packet data structures during PMTU processing. The flaw demonstrates a classic example of insufficient input validation and error handling in network protocol implementations, where untrusted network data can cause system instability.
From an operational impact perspective, this vulnerability poses a significant threat to network availability and system reliability in environments running affected HP-UX versions. Remote attackers can exploit this weakness to disrupt network services without requiring authentication or elevated privileges, making it particularly dangerous in production environments where network uptime is critical. The attack vector is straightforward as it only requires sending specific packet sequences to the target system, which can be accomplished from any network location. Organizations running these older HP-UX versions may experience service interruptions, increased network latency, and potential data loss during attack windows. The vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks, where adversaries leverage system weaknesses to compromise availability. This type of attack can result in business disruption, service degradation, and may require system restarts to restore normal operations, potentially causing cascading failures in dependent systems.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected HP-UX systems with the appropriate security updates from Hewlett-Packard. Organizations should implement network segmentation and access controls to limit exposure to potentially malicious traffic, particularly focusing on restricting network access to systems running vulnerable HP-UX versions. Network administrators should consider implementing intrusion detection systems with signature-based detection capabilities for identifying attack patterns associated with this vulnerability. Additionally, system administrators should monitor network traffic for unusual packet patterns that may indicate exploitation attempts, and implement rate limiting or packet filtering rules to prevent malformed PMTU packets from reaching vulnerable systems. The vulnerability's nature suggests that implementing proper input validation and robust error handling mechanisms in the TCP/IP stack would provide adequate protection against similar issues, aligning with the principle of least privilege and defense in depth strategies recommended by cybersecurity frameworks.